I. Field of the Invention
The present invention relates to thin films of refractory metal disposed upon substrates, and more particularly, to a method for the improvement of the conductivity of such refractory metal thin films.
II. Prior Art
Thin films of refractory metals are typically deposited on insulating and semiconductor substrates (e.g. silicon) by either sputtering or chemical vapor deposition (CVD). The tools employed for the sputter depositions typically have only "moderate" base pressures upon evacuation, typically greater than 1.times.10.sup.-7 torr pressure. Accordingly when the metal selected is sputter deposited onto the substrate, small but significant amounts of oxygen, originating from the moderate-vacuum environment, either directly from the ambient or from the sputter target, are incorporated into the film, typically at grain boundaries. The identical process may also occur in films produced by CVD in a moderate vacuum reactor. Additionally in some cases the oxygen may be introduced via oxygen atoms present in the CVD precursor molecules themselves or via oxygen containing impurities in a carrier gas. The effect of the oxygen impurity in the films is to increase the resistivity of the films, which is a highly undesirable feature for many applications.